Auto-brightness control technology depending on user’s pupil area

An ambient illuminance sensor of a mobile device does not always accurately measure the light that directly affects human perception of the display brightness. Thus, viewing high-luminance displays under low-light conditions causes an unbearable glare, while viewing low-luminance displays under bright-light conditions causes very poor visibility. In this paper, an automatic brightness control (ABC) technology depending on pupil area is proposed. The experimental results revealed that the pupil area decreases by 33% as the ambient illuminance increases tenfold. A linear relation was also observed between appropriate display luminance and logarithm of ambient illuminance in our previous investigation. As a result, the comfortable display luminance is proportional to the relative pupil area, which enables us to propose a novel ABC technology depending on the pupil area.